<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
<style>
    .box{
        width: 200px;
        height: 200px;
        background-color: rgb(187,150,156);
    }
</style>
</head>
<body>
    <div id="app">
        <!--
            动态设置style
            :style="{ css属性名：css属性值}"
        -->
       <div class="box" :style="{width: '300px',background-color: 'yellowgreen'}"></div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.js"></script>
    <script>
        const app = new Vue({
            el:'#app',
            data:{
                
            },
        })
    </script>
</body>
</html>